Pubs, clubs and restaurants will be limited to 100 people per venue, with one person per four square metres and no stand-up drinking.
Table bookings and home gatherings will be capped at 10 people, with funerals limited to 50 and weddings to 150.
Gyms and recreation centres will be closed for two weeks and community sport fixtures will be cancelled – but schools will stay open.
General mask wearing is strongly advised where social distancing is not possible.
South Australia will face new coronavirus restrictions from midnight as the state battles a cluster of 17 new cases. Pictured: Residents queue for Covid testing in Victoria Park, Adelaide
Hundreds of people have lined up to get a coronavirus test at a pop-up clinic in Parafield, northern Adelaide on Monday morning as a family cluster in the suburb continues to grow
Western Australia, Queensland, Tasmania and the Northern Territory have imposed quarantine for people arriving from SA, while Victoria has introduced extra screening.
Adelaide residents said they had witnessed panic buying as people rushed to the shops to stock up in anticipation of restrictions. International flights to the city have been suspended.
Seventeen of the 18 cases recorded are members of the same family.
SA Health authorities believe the outbreak started when a worker at Peppers Hotel quarantine in Adelaide’s CBD brought the virus home to a large family.
A couple, a woman in her 50s and a man in his 60s, then gave the disease to an 80-year-old woman who was one of their mothers.
The woman went to Adelaide’s Lyell McEwin Hospital for testing.
Contact tracing is underway for about 90 staff and patients at the hospital who may have come into contact with the woman.
South Australia’s Chief Public Health Officer Nicola Spurrier revealed the spike on Monday.
‘It looks like we’re in the beginning or early part of what could be a second wave but we have time to get on top of it,’ she said.
Cars queue for the COVID-19 testing facility at Victoria Park, just outside the Adelaide CBD on Monday
STATES REACT TO SA CLUSTER
NSW: Border with SA remains open, but Gladys Berejiklian says she is watching the situation ‘carefully’
VIC : Has not closed its border with SA, but travellers entering the state will be interviewed at Melbourne airport and could be made to take a rapid test
QLD : Has declared Adelaide a hotspot. Anyone who arrives from the SA capital after 11.59pm Monday must undergo hotel quarantine for 14 days. Travellers already in Queensland from last Monday must get tested and quarantine where they are for 14 days
TAS/WA/NT: Mandatory 14-day quarantine for anyone arriving from South Australia, with those already in the state made to self-isolate
Warnings were issued for a range of public bus services and various locations including a swimming centre, fruit shop, two supermarkets, a chemist, a GP surgery, a department store and a hotel in the centre of Adelaide city.
Premier Steven Marshall said: ‘I want to assure all South Australians that we are working around the clock to stay ahead of this cluster. No effort will be spared to slow and stop the spread.’
Waiting times at testing stations in Adelaide have blown out to hours as thousands of people rush to get checked for COVID-19.
The so-called Parafield cluster, based in Adelaide’s north, has grown to 17 cases with at least two schools and a fast-food restaurant closed after being linked to the outbreak.
An Anglicare aged care centre at suburban Brompton was also placed in lockdown after two staff members tested positive.
A pop-up testing station has been established at the Parafield Airport as officials frantically try to contain the spread.
Hundreds flocked to it and other testing facilities on Monday, with long lines forcing some to wait for hours.
Mr Marshall briefed Prime Minister Scott Morrison and accepted extra ADF troops to help with contact tracing.
The premier said the cluster had been linked to someone who worked at one of Adelaide’s quarantine hotels but it was too early to say what went wrong.
‘My focus at the moment is doing everything I can, that the government can to get on top of this as quickly as possible,’ he said.
SA Health advised students at the Mawson Lakes School and pre-school not to attend on Monday after a student was identified as a close contact of one of the positive cases.
The Thomas More College was also closed after a confirmed case of coronavirus, and the Hungry Jack’s outlet at Port Adelaide was shut.
Western Australia, Tasmania and the Northern Territory have all declared South Australia a coronavirus hotspot and shut their borders to the state. Pictured: a Qantas flight to Adelaide last month
Another case was linked to the Yatala prison in Adelaide, with the Courts Administration Authority cancelling all appearances by prisoners held in the jail, either in person or by video link.
NSW Premier Gladys Berejiklian said she was monitoring the interstate situation closely and insisted the borders would remain open to all, saying everyone needed to learn to live with Covid and the inevitable outbreaks.
‘You can’t shut down borders and disrupt lives every time there is an outbreak and disrupt businesses.
‘We need to have confidence, not just in our own system, but the system in other states to be able to get on top of the virus,’ she told reporters on Monday.
ADELAIDE’S COVID-19 OUTBREAK – WHAT WE KNOW SO FAR
By Lauren Ferri, for Daily Mail Australia
A worker at the Peppers Hotel in the Adelaide CBD is believed to have caught the virus from an international traveller and then infected her large family.
The couple – a woman in her 50s and a man in his 60s then gave it to an 80-year-old woman, who is one of their mothers.
Elderly woman visited the Parafield Plaza Asian supermarket between 10:30am and 11:30am on Thursday without knowing she was infectious.
Growth in the Parafield outbreak led to the family cluster in South Australia rising to 17 cases on Monday.
SA Health authorities believe the outbreak started when a worker at Peppers Hotel’s quarantine facility in Adelaide’s CBD brought the virus home. The CBD hotel is pictured
Western Australia has since forced all arrivals from SA since Saturday to self-quarantine for 14 days.
More than 90 people already forced into quarantine as dozens of locations put on high alert:
Anyone who was in the emergency department at Lyell McEwin Hospital between 5pm Friday 13 November and 4am on Saturday 14 November told to self-isolate immediately.
Prisoners are being tested at Yatala Labour Prison after an employee who was a close contact of the family contact contracted COVID-19.
Anyone who visited Parafield Plaza Supermarket between 10.30am and 11.30am on Thursday November 12 told to watch for symptoms.
Mawson Lakes Primary School has been closed for 24 hours after a close contact of a student tested positive to the virus.
Thomas More College in north Adelaide has closed for at least 24 hours after a student at the school tested positive – and Hungry Jack’s in Port Adelaide has also been closed for a deep clean.